vas rectum

Noun

vas rectum (plural vasa recta)

1. (dated, plural-normally) A straight seminiferous tubule conveying semen from its pertaining tubulus seminiferus contortus (convoluted seminiferous tubule) to the rete testis of the testicle that contains it; now more commonly called the tubulus seminiferus rectus (straight seminiferous tubule).
   • A yellowiſh ſemen is generated in the vaſcula ſerpentina, is ſent down into the vasa recta, and thence depoſited in the rete under the albuginea.1750, Albert Haller, “Of the paſſages of the ſemen” in The Philoſophical Tranſactions (1743–1750) Abridged X (1756), ed. John Martyn, page 1,092
   • One single, straight duct termed vas rectum, which joins the rete testis at a right angle. The vasa recta are very slender, and easily give way when injected.1843, Thomas Blizard Curling, “A Practical Treatise on the Diseases of the Testis”, in The Edinburgh Medical and Surgical Journal, LX:ii, page 216
2. (plural-normally, sometimes more fully) Any one of many straight capillaries in the kidney that branch off from the arteriolae efferentes (efferent arterioles) of juxtamedullary nephrons, enter the medulla, and surround the loop of Henle, where they function to absorb water and to secrete salt and urea into the renal interstitium, thereby facilitating the production of concentrated urine.
   • Long and almost straight vessels (vasa recta), into which the efferent vessel of those tufts situated at the bases of the pyramids, divides.1858, Lionel Smith Beale, Illustrations of the Constituents of Urine, Urinary Deposits, and Calculi, Fig. 1. g., page 3
   • The vasa recta are capillaries, mostly derived from the efferent arterioles of juxtamedullary nephrons, which have a ‘hairpin’ arrangement and dip far down into the renal medulla.2000, Christopher J. Lote, Principles of Renal Physiology, fourth edition, § 6.4, page 78
3. (plural-normally) Any one of numerous straight arteries that branch off from the arcades of the mesentery of the jejunum and ileum whence they head toward the small intestine.
   • Bleeding from colonic diverticula is caused by rupture of the underlying vas rectum.1990, Jay H. Stein, Internal Medicine, third edition, page 395